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Old telephone line wiring? help!

Posts: 2
Registered: ‎27-12-2017

Old telephone line wiring? help!


I recently purchased a new house which has BT openreach master socket (looks reasonably new).

I set up new BT Fibre Infinity package which works fine - now I'm decorating I spotted some old junction box near the window ledge which holds a mess of wires which leads to a wire outside the front of the property into the ground! Is this an old telephone line aka can I rip this thing out or is this actually my phone line connection - if so I'm worried how safe this is and can an electrician simply update it for me?

I don't know if BT will tell me if they used a brand new connection line or just linked the master socket to this - if they did I'd question that since the wires look cut and the colours seem to be transferring and fading!

Any help/advice would be great!


Posts: 251
Thanks: 107
Fixes: 15
Registered: ‎20-04-2016

Re: Old telephone line wiring? help!

The black cable with green/black and orange/white pairs is the incoming BT line.  Do the white cables go to your master socket ?  If so I suspect this junction box is live.  This box belongs to BT but should have a cover over it - legally you aren't allowed to mess with it.


The second white cable looks to be disconnected, my guess is at some point time in time you had a second line on the orange/white pairs and this went off to a second master socket somewhere.

Posts: 11,669
Thanks: 5,186
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Registered: ‎30-06-2016

Re: Old telephone line wiring? help!

One of the cream cables looks disconnected so this can be carefully untangled from the other cable and safely ripped out. The other looks like it goes to your master socket, only two cores are required at this stage.  Can you trace the cable back to your master socket?

Whilst the exposed terminals are not hazardous it does look unsightly, your choices are:

1. Leave it

2. Make your owm cosmetic cover

3. Get a third party to change it, replacement boxes are available on line but be aware that doing this contravenes the rules.

4. Pay through the nose for BT to do it.

One final thought, if BT have recently changed/fitted the master socket you might be able to get them back to do the job properly free of charge. Assuming that the black cable is the incoming cable then the master socket should really have been fitted here unless the old cable constitutes what is a proper extension cable.

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Posts: 2
Registered: ‎27-12-2017

Re: Old telephone line wiring? help!

Many thanks to you both for your responses.

I took up the old carpet and found the wire below the master socket. It follows back towards the box via the skirting and chased into the walls so I will probably won't be yanking it anytime soon. I reckon it was replaced a few years back as there was layers of wallpaper to take off and the additional wiring I think was an extra phone line on the other side of the wall which is now gone. Just so bulky and unsightly on the windowsill.

I will now find a cover to conceal it but by all means I won't touch it!

Thanks again, most helpful.
Rising Star
Posts: 52
Thanks: 23
Fixes: 1
Registered: ‎09-01-2018

Re: Old telephone line wiring? help!

It's safe, just untidy.

I agree that one of the wires to the right certainly isn't doing anything but the other could be your in-coming line.  Telephone wires usually have at least four cores but only two or three are used and the spares tend to be left loose at installation — they won't have fallen off.

As for the wire going into the ground, do you have an over-head wire to your house from a pole?  If not that could be the wire from the exchange.  If it's a bare one it's an old Earth.  Until the 1960s these were installed as part of the lightening protection arrangements. They were also used on Shared Service (Party) Lines but these were relegated to history in the early-80s.

Going on the core colours I'd bet that the light-colored wires were put in at the same time as the Master Socket.

A simple thing would be to put some gaffer tape over the top of the box and then paint it.  As others have said, you can't legally replace it yourself and BT would odds-on charge you to tidy it up.

Seasoned Hero
Posts: 6,399
Thanks: 1,782
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Registered: ‎06-11-2014

Re: Old telephone line wiring? help!

Now there's a name I recognise from somewhere else!! Grin


Anyway, that's a GPO Block Terminal 35A, there's complete (but used) one on ebay at the moment:


But technically it is up to BT to maintain it as it's before the master socket, and exposed terminals like that are a shock risk given that when a phoneline rings, you can get up to about 100-ish volts AC across the A & B wires, which believe me wakes you up if you're not paying attention... Shocked